Add MIGraphX/half deps and use AMD onnxruntime wheel for ROCm 6.1.3

Per AMD docs (rocm.docs.amd.com install-onnx):
- apt install migraphx, migraphx-dev, half (required by onnxruntime-rocm)
- Switch to AMD-hosted wheel: onnxruntime_rocm-1.17.0-cp310 from repo.radeon.com
- Pin numpy==1.26.4 (numpy 2.0 incompatible with this wheel)
- Add MIGraphXExecutionProvider to provider list in engine.py

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Dockerfile.rocm

@@ -14,6 +14,9 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     ffmpeg \
     libsndfile1 \
     hipblas \
+    migraphx \
+    migraphx-dev \
+    half \
     && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app